This is a truly impressive implementation, based on previous work by Jonathan Feinberg [1]. The display uses SVG, but the character outlines are computed by canvas bitmaps. Then, Jason implemented hierarchical bounding boxes to accelerate the intersection checks. Be sure to play with the draggable "0" and "1" letters beneath the demo!
Try clicking on words to navigate between word clouds. The cross-fade transition is beautiful, and words that overlap between clouds transform in their new position.
Non-English word clouds look amazing, too:
http://www.jasondavies.com/wordcloud/#http%3A%2F%2Fsearch.tw...